docs: def create_notification_channel(self, callback_url, calendar_ids=()):
          """Create a new channel for receiving push notifications.
  
          :param string callback_url: The url that will receive push notifications.
          Must not be longer than 128 characters and should be HTTPS.
          :param tuple calendar_ids: List of calendar ids to create notification channels for. (Optional. Default empty tuple)
          :return: Channel id and channel callback
          :rtype: ``dict``
          """
          data = {'callback_url': callback_url}
          if calendar_ids:
              data['filters'] = {'calendar_ids': calendar_ids}
  
          return self.request_handler.post('channels', data=data).json()['channel']